did an experiment. I have an original iPad mini, and I hadn’t yet gotten around to updating it to iOS 8 (in part because the over-the-air updater told me it needed 4.9 GB in free space, and it’s only a 16 GB device, and I didn’t have enough free space). I loaded it with only iOS 8 and Apple’s apps. I installed all of Apple’s apps: the iWork apps, iMovie, Garage Band, Find My iPhone, Remote, etc.

[...]

Apple should simply not sell 16 GB devices any more. If, after installing just the basics, there’s only half the advertised space available (I know, I already lost a couple of GB because of marketing), then users can’t put a lot of content on them. Many won’t care, but once you start downloading a few games, you get into a situation where there’s not enough room to apply updates, because they need so much free space. (And, as a commenter pointed out below, Apple still sells the iPhone 5c with only 8 GB; imagine the results if I tried this on one of those devices.)
Once again, that Apple still, in 2014, sells 8 and 16GB devices is inexcusable and downright punitive.